Bronze in the 400m proved to be a bittersweet consolation for US track legend Allyson Felix as she drew level with Jamaicans Merlene Ottey and Usain Bolt on having won 14 world championships medals.

United States' Allyson Felix after taking the bonze medal in the Women's 400m final during the World Athletics Championships in London on Wednesday. (AP Image)

London: Bronze in the 400m proved to be a bittersweet consolation for US track legend Allyson Felix as she drew level with Jamaicans Merlene Ottey and Usain Bolt on having won 14 world championships medals.

Felix has also bagged an incredible nine Olympic medals including six gold. Of her 14 world medals, nine have been gold, while 12 in total were won as part of the US relay team.

Jamaican Bolt, in his swansong season, can move to 15 with a medal in the 4x100m relay this weekend, but Felix is slated to run both the 4x100 and 4x400m relays for the US team, which could take her to 16.

Felix crashed through into bronze in Wednesday's 400m after Bahamas rival and race leader Shaunae Miller-Uibo faltered 20 metres from the finish line.

In pouring rain, Felix's unheralded teammate Phyllis Francis ripped up the form book to claim a shock gold, with Bahrain's Salwa Eid Naser taking silver just ahead of Felix.

"I cannot lie, I am disappointed to lose one gold tonight but the championships is not over yet so we keep going," said Felix, who kicked off her startling medal haul with a 200m silver medal at the 2004 Olympics in Athens, her first global gold coming in the 200m at the Helsinki world champs a year later.

"But this was the race that mattered to me, the individual race, that is what it is about. So to come up short tonight is never fun. But I am happy for my team mate. At this level, you cannot underestimate anyone.

"You always go into a race wanting to win and that was my goal all season, so when you fall short of that mark it's definitely disappointing.

"At the same time I feel very grateful to have done this for a long time and still be competing at the top."

Felix, now 31, added: "I am not hurt, it is just the 400m, it is what it is. The conditions were the same for everyone, I am not sure if that was the factor tonight. It all seems wet to me.

"I still feel it is not over yet. I still did not give everything so I am excited to keep going until 2020" and the Tokyo Olympics.

Felix played down the idea that she was not given enough credit for her astonishing longevity and medal haul.

"You know I never really think about it too much. I love the sport and I'm passionate about it. I'm really proud of what I've done over the past 14 years, and as long as I'm enjoying myself then that is enough for me," she said.